Funds are requested to enable scientists to participate in the seventh bi-annual Gordon Research Conference on Mammalian DNA Repair, to be held in Ventura, CA, Feb. 7- Feb. 12, 1999. The selected speakers are current leaders in the fields of DNA repair and related cellular processes. Besides providing a forum for these experts to present their most recent results and ideas, the conference will facilitate wide- ranging interactions among all attendees through Plenary Discussion Sessions and at posters. Selected poster presenters (generally students and younger scientists) will be given the opportunity to highlight their research results in short presentations, to stimulate debate following the plenary talks. (Several overhead transparencies, but no slides will be permitted for these "Discussion Points"). The Conference is normally oversubscribed with attendance limited to 135 participants. The attendees will be chosen globally from universities, research institutes, and government and industrial research labs. Every effort will be made to select a well-balanced mix of individuals ranging from leads in mammalian DNA repair to younger scientists new to the filed. A concerted attempt will be made to identify and attract qualified minority scientists to the conference. The 1999 Conference differs from the previous one, in that it will focus more narrowly on mammalian systems. This reflects the explosive growth of the DNA repair field and the exciting, new data linking DNA repair to human genetic disease and cancer (e.g. BRCA gene mutations that predispose to breast cancer appear to have roles in DNA repair). The first session will feature a keynote address by Dr. Richard Setlow and two other special lectures, by Prof. Jacqueline Barton and by Dr. Thomas Lindahl. The following eight sessions will define areas in which exciting new information is emerging but in which experts may disagree. The session topics include: Repair of endogenous damage, in nuclei and mitochondria; Translesion synthesis and repair of mismatches; DNA repair enzyme structure and substrate interactions; Nucleotide excision repair- role of transcription; Base excision repair- overlap with other pathways; Inducible responses and cell cycle checkpoints; Cellular localization of repair and effects of bound proteins; and DNA repair deficiency in human genetic disease. In summary, this Conference will examine DNA repair as a key component in the genomic surveillance that is so crucial to the overall integrity and function of mammalian cells. Recent discoveries have catapulted DNA repair into a pivotal position in fundamental research in the fields of oncology, aging, environmental health, and developmental biology. We hope to highlight the most promising and exciting avenues of research in robust discussions at this conference.